Performance of heterogeneous catalytic ozonation process using Al2 onanoparticles in dexamethasone removal from aqueous solutions

Abstract

Dexamethasone (DEX) is a type of corticosteroid medication that is commonly used for the treatment of human and animal diseases. The presence of its residual in wastewater can cause human mutagenicity and carcinogenicity. Therefore, this study aimed to evaluate the efficiency of the catalytic ozonation process (COP) in the presence of aluminum oxide (Al2 O3 ) nanoparticles in DEX removal. This experimental study was conducted in a laboratory and batch scale. In this study, a batch reactor with a diameter of 5 cm and a height of 45 m was used. The ozone concentration was deter-mined using an iodometric method. The effects of some parameters such as solution pH, contact time, ozone concentration, and catalyst concentration on the process efficiency were investigated. Al2 O3 nanoparticles were characterized by the scanning electron microscopy X-ray diffraction and Fourier-transform infrared spectroscopy analyses. The DEX concentration was measured using an ultraviolet light spectrophotometer at a wavelength of 241 nm. According to the results, the optimal value of solution pH and catalyst dose in the COP was obtained to be 10 and 0.5 g/L, respectively. Under the optimal conditions, the process efficiency was 100% in the presence of 10 mg/L of the initial pollutant concentration after 12 min, and magnesium oxide nanoparticles caused an increase in the removal efficiency (67%) compared to the single ozonation process without catalyst). Due to the lack of sludge production and accessibility, this process can be used as a useful approach for the removal of a wide range of pharmaceutical compounds.